Alkylbenzene photooxidizing process with oxygen to prepare aromatic aldehyde and aromatic acid

Abstract

The present invention belongs to the field of preparation of aromatic aldehyde and aromatic acid, and is especially alkyl benzene photooxidizing process with oxygen to prepare aromatic aldehyde and aromatic acid. Alkyl benzene is oxidized effectively into corresponding aldehyde and acid with oxygen or air in mild condition in the presence of common photosensitizer and under irradiation of ultraviolet ray or visible light. During oxidation, the reaction time is controlled to obtain high yield of aldehyde and acid.

Description

technical field

[0001] The invention belongs to the field of preparing aromatic aldehydes and acids, in particular to a method for preparing aromatic aldehydes and acids by photooxidizing alkylbenzene with oxygen. Background technique

[0002] In industry, aromatic aldehydes and acids are important chemical intermediates widely used in pharmaceuticals, dyes, pesticides and fragrances. Its conventional preparation method is to oxidize alkylbenzene with oxidant (mainly inorganic oxidant such as high-valent cobalt, manganese, etc.). However, these oxidizing agents usually cause environmental pollution problems and are relatively expensive. Therefore, there is an urgent need to use cheap and environmentally friendly oxidants, such as oxygen, for clean and efficient production (J.Am.Chem.Soc.2003, 125, 12850-12859). In the thermochemical reaction process, although the benefits of using oxygen as an oxidant are obvious, the activation of oxygen generally requires very harsh cond...

Examples

Embodiment 1

[0023] Dissolve 2,4,6-triphenylpyranyl boron tetrafluoride and toluene in a glass reactor filled with dichloromethane at a molar ratio of 1:10, stir and fill at an oxygen pressure lower than three Oxygen for 20 minutes, and then react with a 100-watt mercury lamp (light <310 nm is filtered out). Oxygen was charged after every 4 hours of reaction. After reacting at room temperature for 10 hours, the reaction is terminated, and as a result, the total yield of benzaldehyde and benzoic acid can reach more than 90%.

Embodiment 2

[0025] Dissolve 2,4,6-triphenylpyranyl boron tetrafluoride and p-xylene at a molar ratio of 1:20 in a glass reactor filled with dichloromethane. Stir and oxygenate for 15 minutes, and then react under irradiation with a 100-watt mercury lamp (light <310nm is filtered out). Oxygen was charged after every 2 hours of reaction. After reacting at room temperature for 5 hours, the reaction is terminated, and as a result, the total yield of p-benzaldehyde and p-benzoic acid can reach more than 95%.

Embodiment 3

[0027] Dissolve 2-p-methoxy-4,6-diphenylpyranyl boron tetrafluoride and p-xylene at a molar ratio of 1:10 in a glass reactor filled with dichloromethane. Stir and oxygenate for 20 minutes under an oxygen pressure of 1 atmosphere, and then react under irradiation with a 500-watt tungsten lamp (the light of <420nm is filtered out). Oxygen was charged after every 4 hours of reaction. After reacting at room temperature for 10 hours, the reaction is terminated, and as a result, the total yield of p-tolualdehyde and p-toluic acid can reach more than 72%.

technical field

[0001] The invention belongs to the field of preparing aromatic aldehydes and acids, in particular to a method for preparing aromatic aldehydes and acids by photooxidizing alkylbenzene with oxygen. Background technique

[0002] In industry, aromatic aldehydes and acids are important chemical intermediates widely used in pharmaceuticals, dyes, pesticides and fragrances. Its conventional preparation method is to oxidize alkylbenzene with oxidant (mainly inorganic oxidant such as high-valent cobalt, manganese, etc.). However, these oxidizing agents usually cause environmental pollution problems and are relatively expensive. Therefore, there is an urgent need to use cheap and environmentally friendly oxidants, such as oxygen, for clean and efficient production (J.Am.Chem.Soc.2003, 125, 12850-12859). In the thermochemical reaction process, although the benefits of using oxygen as an oxidant are obvious, the activation of oxygen generally requires very harsh cond...

Examples

Embodiment 1

[0023] Dissolve 2,4,6-triphenylpyranyl boron tetrafluoride and toluene in a glass reactor filled with dichloromethane at a molar ratio of 1:10, stir and fill at an oxygen pressure lower than three Oxygen for 20 minutes, and then react with a 100-watt mercury lamp (light <310 nm is filtered out). Oxygen was charged after every 4 hours of reaction. After reacting at room temperature for 10 hours, the reaction is terminated, and as a result, the total yield of benzaldehyde and benzoic acid can reach more than 90%.

Embodiment 2

[0025] Dissolve 2,4,6-triphenylpyranyl boron tetrafluoride and p-xylene at a molar ratio of 1:20 in a glass reactor filled with dichloromethane. Stir and oxygenate for 15 minutes, and then react under irradiation with a 100-watt mercury lamp (light <310nm is filtered out). Oxygen was charged after every 2 hours of reaction. After reacting at room temperature for 5 hours, the reaction is terminated, and as a result, the total yield of p-benzaldehyde and p-benzoic acid can reach more than 95%.

Embodiment 3

[0027] Dissolve 2-p-methoxy-4,6-diphenylpyranyl boron tetrafluoride and p-xylene at a molar ratio of 1:10 in a glass reactor filled with dichloromethane. Stir and oxygenate for 20 minutes under an oxygen pressure of 1 atmosphere, and then react under irradiation with a 500-watt tungsten lamp (the light of <420nm is filtered out). Oxygen was charged after every 4 hours of reaction. After reacting at room temperature for 10 hours, the reaction is terminated, and as a result, the total yield of p-tolualdehyde and p-toluic acid can reach more than 72%.